U.S. Pat. No. 6,516,046 B1 describes a method for exact positioning of a patient for radiotherapy or radiosurgery comprising the steps of pre-positioning the patient relative to a linear accelerator, producing at least one X-ray image of the patient or one of body parts in the vicinity of the radiation treatment target, mapping the X-ray image and detecting a positional error on the basis of specific landmarks in the image.
U.S. 2003/0081734 A1 describes a low-dose exposure aided positioning system for digital radiography, a system and a method for improved imaging of a patient through the use of low-dose exposure aided positioning is provided, the patient is positioned in the X-ray system and then imaged with a low-dose pre-shot to verify the positioning of the patient. If the patient's positioning is acceptable, the patient is then imaged with a full-dose X-ray exposure.
US 2014/0185740 A1 describes an automatic scanning and positioning apparatus for a scout image, the apparatus comprising a receiving means, for receiving a scout image of a subject obtained through scouting scanning; a checking and determining means, for automatically checking at least one position in the scout image according to a plurality of information contained in the scout image, and automatically determining a scanning scope based on the at least one position.
In many fields of digital X-ray radiography bad quality of images is induced by improper or inappropriate patient positioning that has a deep impact on the quality of recorded images.
Positioning errors are one of the most frequently done observed errors in X-ray acquisition. Positioning errors may degrade the diagnostic value of a radiograph, e.g. a lung tissue abnormality is overlaid with the scapula due to malpositioning errors, and in consequence the abnormality is overlooked. Positioning errors may also preclude the desired diagnosis, e.g. the target organ is not completely visible (e.g. missing lung, missing lung apex), or acquired from an imperfect angle (e.g. for an orthopaedic question).
In such cases the X-ray acquisition has to be repeated. Strong variability in acquisition not well adhering consistently to pre-defined standards was also stated as the main problem in image acquisition in the area of tuberculosis in our investigations. Thus, following adherence to positioning standards is an important factor for the value of X-ray images.